A very strange experience indeed. Anytime I called them with just a hint of a fraud suspicion I promptly got a fresh card with new number.

The only thing that did make sense was that Amex said they can't help you reverse a pre-authorized charge from TACA.

That much is true. To do a charge back it has to be a posted charge, not just a pre-auth and that can take a few days to settle.

But in any case since you clearly told Amex you never use the card for airline tickets, let alone this flight to Costa Rica, they should have blocked your card immediately and issued a fresh one.

The prelude to your story is also of concern. That a card shows up in your drive way. A replacement card you never ordered. Either the rep who explained to you why a card showed up in your mailbox explained it wrong or you may be the victim of ID fraud.

I'd call Amex one last time and if the story doesn't make sense I would cancel all my cards with all banks and get replacements. Furthermore I'd pull my own credit reports from Experian, TransUnion et al to scan for anything I didn't know about.